The present invention relates to endless belt and roll assemblies of the type which are used in vehicles and conveyers. Thus, in such constructions the endless belt extends between and is guided around the pair of rolls. Such an endless belt may be made up of a series of interconnected elements or may be in the form of a continuous sheet material.
Assemblies of the above type are already known in connection with vehicles which are of the endless track type, such vehicles generally having one roll such as a front roll which is capable of swivelling about an upright axis for the purpose of steering the vehicle. In this connection reference may be made to Finnish Pat. Nos. 48,814 and 50,498. With such constructions when one of the rolls around which the endless belt extends is turned about an upright axis, for steering the vehicle, the endless belt contracts on one side and lengthens on the opposite side while the vehicle executes a turn. Thus, such an endless belt is capable of assuming a curved configuration when the vehicle turns.
Such an endless belt or track generally has a central endless band or equivalent reinforcing or stiffening structure which extends in the direction of travel of the vehicle and which is capable of bending substantially according to the curvature required by the turning radius of the vehicle, this central band or the equivalent thereof being substantially non-stretchable in a longitudinal direction. However, on both sides of this central band the endless belt or track has areas which are capable of stretching or contracting and which are of an accordion or wavy-shaped configuration.
In vehicles of the above type where a roll around which the endless belt or track is guided is capable of swivelling about an upright axis, the curving of the endless belt or track requires the latter to have certain properties.